Abstract: In order to determine seed vigor of forest tree rapidly and automatically, five-lot seeds of China fir and masson pine were used to study the assessment methods of seed vigor by using computer image processing. Firstly, images were captured by a common digital camera from germinated seeds which grew upright on blue germination paper. Then, seedling growth was measured daily for 5 days since 6th day after sowing (DAS) using self-developed seedling length calculating software. The results showed that the seedling length and growth rate generally ranked seed quality in a similar trend compared with field test, and the optimal computer recognition indices were species dependent. Seedling lengths at 6th, 9th DAS (SL6, SL9) were the optimal indices to assess seed vigor of China fir. Seedling length at 10th DAS (SL10) and growth speed (GS) were the optimal indices to assess seed vigor of masson pine. In general, it was feasible to assess seed vigor of China fir and masson pine by using computer image analysis of seedling length and growth rate. The research can provide a reference for seed vigor assessment of small-seed species.