This work is supported by Chinese Natural Science Foundation (Nos. 11133007, 10973037, and 10903026) and partly supported by the External Cooperation Program and the West Light Foundation of the Chinese Academy of Sciences. CCD photometric observations of V753 Mon were obtained with the 60 cm and the 1.0 m telescopes at Yunnan Observatory. The authors thank the referee for useful comments and suggestions that helped to improve the original manuscript greatly.