Abstract: In order to explore effect of different sowing dates on forage yield, growth and over-wintering rate of alfalfa (Medicago sativa L.), experiments were performed in mid-eastern Jilin Province from 2013 to 2014 with Medicago sativa L. ‘Gongnong No.1’. The results showed that seedling emergence days and growth characteristics reduced gradually with the delay of sowing date. Overwintering rate and forage yield were the highest when sowing was conducted on May 9th and May 24th in the second year but were the lowest when sowing was conducted on August 9th. Overwintering rate was 98.95% when sowing was conducted on May 24th. The results implied that early-sowing could increase plant growth, but total yield reduced due to the lower overwintering rate. From the test results of two years, it can be concluded that the optimal sowing date of alfalfa in mid-eastern Jilin Province should be in May. It was better to sow before July 9th.