Background and Aim The Boston Bowel Preparation Scale (BBPS) is a novel bowel cleanliness rating scale that has undergone validation at Boston University Medical Center, Boston, MA, USA. Thus far, there is no standard recognized bowel preparation scale in China. The aim of the present study was to analyze the reliability and validity of the BBPS for the assessment of bowel preparation quality (BPQ) in China. Methods A group of 49 participants from several hospitals in Guangdong province viewed a video demonstration of BBPS provided by Boston Medical Center and participated in a continuing education seminar. Inter-observer reliability was assessed for three testing colonoscopies in the video. Three months later, 13 of the participants repeated the test, and intra-observer reliability was assessed. The BBPS was then applied prospectively in 1012 screening colonoscopies and BBPS scores were compared with polyp-detection rate. Intraclass correlation coefficients (ICC) and weighted Kappa values assessed inter- and intra-rater reliability, respectively. The association of BBPS scores with polyp-detection rates was calculated by 2 tests. Results The inter-observer ICC of BBPS scores was 0.987 (95% CI, 0.9491.0). The weighted Kappa for BBPS scores was 0.671 (95%CI, 0.5070.841). For 1012 screening colonoscopies, the mean BBPS score was 6.9 +/- 1.8. BBPS scores5 were associated with a higher polyp-detection rate (35%) than scores<5 (18%) (P<0.05). Conclusion The BBPS is a valid and reliable measure of BPQ, and this validity and reliability was maintained for Chinese physicians taught via video.