Search engine is one of the mostly-used big data applications. However, search system varies in different platforms and fields, and there are few approaches to evaluate its quality. Search engine for online shopping systems combines text search and classification-based retrieval. It is more difficult to validate and evaluate quality since there are no definite quality standards or testing methods. Some quality factors and relational indicators are provided in this paper through studying on search system of online shopping platform, Experiments and comparisons on different shopping platforms are also performed to show the quality problems of search engines in shopping platforms. The study results indicate the feasibility and effectiveness of the proposed quality evaluation approach.