Fifteen to twenty days. Freshmen's military training usually lasts for 15 to 20 days, because the contents to be studied in 15 to 20 days include the education and training of general rules, the training of parade movements, the simulation training and tactical training of light weapons shooting, the fighting foundation, battlefield medical rescue, nuclear, biological and chemical protection training, etc. It is to improve students' self-care ability, cultivate ideological independence, cultivate hard-working, hard-working, strong perseverance and collectivism, and develop a good life style.