Background: Research in China has been rapidly gaining momentum, but as yet there is no systematic evaluation of quality of reporting in randomized controlled trials (RCTs) on the treatment of cancer pain conducted in China. Therefore, an assessment in this field is an imperative issue. Methods: A PubMed search of reports published between 1994 and 2009 followed by an examination and critical appraisal of reporting in RCTs on the treatment of cancer pain was conducted in China. All reports had been examined to describe their general characteristics and evaluate the quality of their reporting. Quality of reporting was assessed against a subset of criteria adapted from the Consolidated Standards of Reporting Trials (CONSORT) statement. Results: A total of 46 RCTs were included in full text. The frequency of RCTs was found to increase over time: from one (2.2%) in 1994-1997 to 28 (60.9%) in 2006-2009. There were fewer papers published in this field in foreign journals, as funding sources and opportunities for collaborative research with foreigners are still limited. Visual analogue scales were the main method of cancer pain evaluation (19 reports; 41.4%). Only 12 studies (26.1%) are deemed to have authentic randomization and 36 papers (78.3%) provided no information about blinding of either participants or investigators. In 22 papers (47.8%), there was no information about the length of time for which participants were followed. Only 15 (32.6%) of the included trials reported approval by an ethics committee and 17 (37.0%) adequately discussed informed consent. Conclusion: The quality of reporting in RCTs on the treatment of cancer pain conducted in China needs to be improved. Three critical steps should be strictly conducted including randomization, blinding and follow-up. Reporting of RCTs in this field conducted in China should meet and keep up with the standards of CONSORT statement.