Machine reading comprehension (MRC) is a typical natural language processing (NLP)task and has developed rapidly in the last few years. Various reading comprehension datasets have been built to support MRC studies. However large-scale and high-quality datasets are rare due to the high complexity and huge workforce cost of making sucha dataset. Besides most reading comprehension datasets are in English and Chinesedatasets are insufficient. In this paper we propose an automatic method for MRCdataset generation and build the largest Chinese medical reading comprehension dataset presently named CMedRC. Our dataset contains 17k questions generated by our auto-matic method and some seed questions. We obtain the corresponding answers from amedical knowledge graph and manually check all of them. Finally we test BiLSTM andBERT-based pre-trained language models (PLMs) on our dataset and propose a base-line for the following studies. Results show that the automatic MRC dataset generation method is considerable for future model improvements.