Greenhouse environmental regulation can effectively improve crop production conditions. But due to the cost, acceptance and other reasons, most farmers use experience-based methods or simpler methods to control the greenhouse environment. In this situation, how to simply and effectively regulate greenhouse temperature and humidity accurately is a pressing issue in current greenhouse production. Firstly, a modern greenhouse intelligent monitoring system based on Internet of things was designed. The experiments of cooling, dehumidification, humidification and fully closed equipment were designed, and the mathematical models of temperature and humidity under closed greenhouse were constructed. By comparing the simulated values without equipment operation under the same conditions with the measured values after equipment regulation, a temperature and humidity control method was proposed according to the time period of crop growth demand and the size of equipment control capacity, and the experimental verification was carried out. The results showed that the subsection and multi-interval control strategy can effectively regulate the temperature and humidity. The temperature within 59.46% of the day was in the target range, and the humidity within 66.80% of the day was in the target range. The equipment operated stably without frequent opening and closing of the equipment. The subsection and multi-interval control strategy put forward an idea for greenhouse environmental control, combined with the typical IoT structure, remote automatic control can be realized, and the research results can be directly applied to practice.