Abstract: OBJECTIVE To screen a cell-free DNA(cfDNA) extraction kit which is compatible with the requirements of easy-processing, speediness, low price, and high extraction efficiency to enrich short DNA fragments. METHODS In order to compare recovery among five DNA extraction kits, six kinds of non-human derived DNA fragments were added into healthy human plasma. Those DNA fragments were extracted by five DNA extraction kits and then quantified by real-time quantitative PCR(qPCR). Next, plasma cfDNA originated from breast cancer patients were extracted by DNA extraction kits above. After quantification of six kinds of Kras gene fragments, extraction efficiency was estimated. Besides, evaluation related to cost and process time were investigated. In summary, optimal extraction kits were determined. RESULTS Kit 1 showed the highest recovery with fragments >157 bp(75.5%-87.4%), and the highest quantities of total cfDNA(154.0±10.1)copies·μL^-1 plasma). The cost of each sample was 274 CNY and it spent 73 min on processing one sample. However, a vacuum pump was required for the protocol. Moreover, Kit 2 not only exhibited the highest recovery of the fragments <157 bp(31.8%-33.7%) among five kits, but also gave the highest quantities of cfDNA <145 bp(81.7±6.2)copies·μL^-1 plasma). Total quantities of cfDNA(137.1±13.9)copies·μL^-1 plasma) were slightly lower than Kit 1. The extraction cost per sample was 15.6 CNY, which took 43 min. Notably, special equipment was unnecessary. CONCLUSION Despite the fact Kit 1 is expensive, it can achieve the highest total cfDNA quantities. As for fragments <150 bp, Kit 2 is an excellent and cost-effective choice.