For the vulnerable groups, many scholars believe that we should give them special protection. But there are some problems that follow: how to define the vulnerable groups? Reducing the litigation costs may rise the whole costs; the legal aid is inefficiency, and inclination to the vulnerable groups may be harmful to the judicial, especial for its objectivity, certainty and legitimacy. To solve these problems, we should reduce the whole costs, use contingency fee to help the vulnerable groups, re-emphasize the principle of equality under the law.