The 10kV series of S13 type oil immersed transformer products has successfully passed test in National Transformer Quality Supervision and Inspection Center on the 13^th of July. The products included four S13-M.RL-250 ~ 1600/10 products and four S13-M-250 ~ 1600 / 10 products. The test items included no-load test, load test, short-circuit withstand capability and other test programmes. Compared with 10kV series of S11 ype oil immersed transformer products that share the same capacity, this series can reduced about 25% of no-load loss, reducing energy consumption greatly.