The invention provides a solid phase flow continuous measuring system and measuring method for a pneumatic conveying process. The solid phase flow continuous measuring system comprises an input pipe, a Venturi pipe and an output pipe. The input pipe, the Venturi pipe and the output pipe are located on one straight line. The length of the input pipe and the length of the output pipe are independently greater than or equal to 80 D. The Venturi pipe comprises a contraction section, a throat section and an expansion section, which are communicated successively. The input pipe is communicated with the contraction section and the expansion section is communicated with the output pipe. The ratio of the length Lt of the throat section to the diameter d of the throat section is greater than or equal to 40. The solid phase flow continuous measuring system also comprises a first pressure detector, a second pressure detector, a third pressure detector and a temperature measurer. The system and method realize continuous measurement of solid phase flow from dilute phase to dense phase, with the deviation in the range of +/-5%.