In the regions controlled by the kh

In the regions controlled by the khmer rouge, Chinese schools at first remained open and the Chinese were not subject to special attention, either negative or positive, from the authorities, After Sihanouk joined the rebels in 1971, Overseas Chinese Associations were established in the 'liberated zones' to support the rebel government that he headed.
Without adopting any explicitly anti-Chinese policy, the communists disrupted the economic base of the rural Chinese by eliminating local markets, either through drastically reducing prices or by actually destroying the market stalls. This was another reason for most rural Chinese residents to flee to the cities, where they were also free from the american bombing.
In their policy towards the Chinese (and other ethnic minorities), the khmer rouge appeared to change drastically in 1974. Until then, they had emphasized the multi-ethnic nature of their support, but now their propaganda stressed the khmer identity of the revolution and explicitly warned against other ethnic groups 'splitting' the revolutionary forces. Chinese began to experience discrimination; they fearfully hid their Chinese identity whenever possible, and Chinese associations disappeared from GRUNK areas. This mono-ethnic policy led to the extreme repression instigated after the khmer rouge came to power in April 1975 as Democratic Kampuchea.
In has been estimated that the Chinese population of Cambodia fell from 400000 to 200000 during less than four years of Democratic Kampuchea, the so-called Pol Pot regime. There is little evidence that the regime singled out the Chinese for special treatment, certainly not in its early years, but its obsessive elimination of all social inequality and all Vietnamese 'traitors' redounded tragically on the Chinese.
Faced with two million refugees in Phnom Penh without food, and ferociously committed to national self-reliance, the khmer rouge summarily emptied the cities into the countryside, forcing the urban population, including almost all the Chinese, to become peasants overnight, many of them in undeveloped regions without arable land. One consequence of this move was the widespread starvation and misery of those who could not adapt; this included the Chinese, none of whom had been peasants.
The totalitarian regime's commitment to instant equality went to such extremes in some areas that anyone suspected of middle-class origins was eliminated. The repression was harshly reinforced by a growing paranoia about the Vietnamese threat. In the campaign to eliminate 'traitors,' thousands of khmer rouge supporters, including some of their top leadership, were tortured and killed, among them Hu Nim, Hou Yuon and other Sino-Khmer.
Furthermore, in some localities, leaders applied the Khmer rouge mono-ethnic polity by taking draconian measures against the Chinese, not only forbidding them to speak Chinese or practise any Chinese customs, but executing them if they did not conform. In a few areas, however, Chinese were able to maintain their Chinese identity without reprisal, suffering only economic hardship along with everyone else.
Since China was in the throes of the Cultural Revolution, the Chinese in Democratic Kampuchea received no support from China's representatives in Cambodia. Indeed, overseas Chinese in China were castigated as 'evil capitalists' and China advisers in Cambodia simply enjoined 'forbearance.'