The invention relates to a commonly used drug spermicide for contraception, in particular to biodegradable contraception gel with antibacterial effect, and belongs to an autonomous external contraceptive. On the basis of the biodegradable contraception gel, exact quantitative administration can be realized by virtue of a disposable long cylinder applicator. The antibacterial contraception gel is composed of a spermicide, biodegradable gel and water. The gel is specifically vaginal gel compounded by silk fibroin and chitosan and comprises the following components in mass concentration: 2-8% ofsilk fibroin, 0.5-2% of chitosan, 0.5-2% of carbomer 940 or hydroxypropyl methyl cellulose, 5-12% of glycerol and propylene glycol and the balance of water, and pH value is regulated to be 3.5-5. Theproduct can achieve the effects of rapidly killing sperms and carrying out contraception and birth control, also has antibacterial effect and can prevent and alleviate germ infection in genital tract.Ingredients of the gel are biodegradable, and degradation products can be absorbed and have the effect of alleviating vaginal dryness and atrophy to some extent. The gel preparation fills a needle tube type tool and can be directly injected deep inside a vagina, and the aim of the exact quantitative administration is achieved. The product has good biocompatibility, can not influence pH of the vagina, has no side effect and is worthy of being popularized and applied in clinic.