The invention discloses a photometric method based boat-carrying pH and pCO2 measuring device and measuring method. The measuring device comprises a pretreatment apparatus and a measuring apparatus. The pretreatment apparatus comprises a submerged pump, a seawater collecting pipeline, a seawater discharging pipeline, a seawater sample tank, a filter head, and a first thermostatic water bath. The measuring apparatus comprises a seawater sample injection pipeline, an indicator bag, an indicator sample injection pipeline, a three-way valve, a peristaltic pump, a mixer, a Teflon AF2400 pipeline, a flow-through cell, a waste discharging pipeline, a miniature deuterium-tungsten halogen lamp, a spectrometer, an air thermotank, and a second thermostatic water bath. The provided measuring device can be used to measuring seawater pH and pCO2. In the prior art, the measurement on the sea carbonate system is complicated and tedious, the power consumption cost is high, and the provided device can solve the problem. Furthermore, the measuring device uses the photometric method, thus the measurement precision is high, and the measuring device can be widely applied to sensors.