This study investigates the influence of using five web-based practice units on English verb-noun collocations with the design of a web-based Chinese-English bilingual concordancer (keyword retrieval program) on collocation learning. Thirty-two college EFL students participated by taking a pre-test and two post-tests, and responding to a background questionnaire and an evaluation questionnaire. Results indicated that learners made significant collocation improvement immediately after the online practice but regressed later. Yet, the final performance was still better than students' entry level. Different verb-noun collocation types and learners with different prior collocation knowledge were found to be not equally receptive to the practice effects. Both the online instructional units and the concordancer were acceptable to most participants.