Since online customer review has significant impacts on customer's purchase decision and product sales, it has been regarded as a new marketing tool nowadays. Moreover, some online transactional platforms and sellers are trying to encourage customers to provide reviews of high-quality by offering a reward. With the empirical analysis of 1044 samples from a famous C2C e-platform website, results show that reward can significantly improve the information richness of online customer reviews. However, the sentiment customer expressed remains unchanged. More specifically, customers are inclined to provide more information, specially opinionated and positive information. But customers are unlikely to conceal negative information or change their sentiment polarity and intensity.