Abstract: For the purpose of the optimum dates, the effect of soybean different sowing dates under soybean intercropping with cassava on yield, agronomic characters and economic benefits of soybean and cassava in northwest of Fujian Province were studied. The results showed that in the models of cassava intercropped soybean, when the soybean were sown on the date of March 17, the highest yield of soybean and cassava were 1432.5 kg/hm2 and 20511.0 kg/hm2 respectively, and the highest net income was 2350.50 yuan/hm2. Under growing time of cassava, earlier planting soybean was both good for higher yield, main agronomic characters and net income. The optimum dates of soybean sowing was days in mid March.