The invention discloses a big-data-based urban drainage network monitoring and control system comprising a monitoring module, a data sorting module, a comparison unit, a database, an analysis module,a processor, an acquisition module, an alarm unit, a smart device and a display screen. The monitoring module is configured to monitor sewage drainage information in real time, wherein the sewage drainage information includes a liquid level of a sewage pool, drainage time of the sewage pool, and harmful gas information and the harmful gas includes molecular weight information of harmful gas, temperature information of harmful gas, and gas pressure intensity information. According to the invention, with the analysis module, the sewage drainage flow rate is calculated and the drainage speed of the sewage is obtained, so that the staff member can carry out adjustment conveniently, the too fast or too slow drainage is prevented, and the workload of the staff is reduced. Meanwhile, the alarm unit is used for carrying out corresponding prompting on the mass concentration of toxic gas, thereby enhancing the safety of drainage work and improving the work efficiency.