Informed by two usage-based approaches, this study investigated to what extent different types of computer-based training facilitated English preposition learning among intermediate Chinese learners of English. The design of the pedagogical materials was informed by the cognitive linguistics (CL) framework while the training format was motivated by the competition model (MacWhinney, 1997). A total of 91 participants were randomly assigned to one of four types of computer-based training: animated schematic diagrams with CL explanations, rules, and exemplars (i.e., rule-of-thumb definitions with three example sentences), correctness feedback (i.e., correct vs. incorrect), and the control, who received training on English Articles. For the three prepositional treatment groups, two layers of mediation were provided: (i) implicit prompts to guide decision making in selecting the correct preposition and (ii) explicit feedback on the selection. Results showed that the computer-based training was effective across the three treatment groups, as measured by an untimed grammaticality judgment test and a picture elicitation test. Additionally, on the picture elicitation test, the schematic mediation group outperformed the rule and exemplar mediation group at the posttest and the correctness mediation group at the delayed posttest respectively. The data suggest there is a need to introduce various assessment task types to capture a more holistic understanding of participants' L2 development.