Biodegradability of PBS/jute fibre composites was investigated by compost soil burial test. Regarding the effect of fibre content on the biodegradability of composite, the order of higher weight loss is PBS/10% jute composite > PBS/20% jute composite > PBS/30% jute composite > pure PBS film > bulk jute fibre. The weight loss of PBS/10% jute composite after 180 days is 62.5%. In case of the effect of fibre diameter, the weight losses are found to decrease with the decrease of fibre diameter, because the composite reinforced with finer fibre has better inner-structure. In the effect of surface modification of fibre, the order of higher weight loss is PBS/untreated jute > PBS/alkali treated jute > PBS/coupling agent treated jute, since the hydrophilic behaviour of jute fibre is weakened by surface modification, and the compatibility with hydrophobic PBS is thus improved. Furthermore, the composite of PBS/woven fabric has the highest weigh loss, following by that of PBS/nonwoven fabric and PBS/bulk jute fibre, respectively. The root reasons are the uniformity of fibre distribution in the composite and the interfacial compatibility of fibre and PBS.