Abstract: Aiming at the need of online monitoring of alkali consistency and alkali recovery in domestic dyeing and printing industry, an intelligent differential pressure type alkali consistency meter with wireless communication function is developed according to the alkali’s density-consistency characteristics. With this meter, signal interference problems during long distance transmission in multi-point measurement mode can be effectively resolved, and the cost and complexity for developing a relevant control system can be reduced. Then an online alkali consistency monitoring system for mercerizing machine is developed by adopting the mentioned meter. With this system, a certain concentration alkali can be proportioned, mixed and transported to the target automatically, and alkali recovery and the requirement for reducing the consumption of concentrated alkali can be achieved. According to the experimental results, the measurement range of the system is between 0~770g/L while the consistency control accuracy is ±5g/L, and a half-year field operation of the system approves that the concentrated alkali for processing unit fabric can be reduced by more than 15%.