The work is devoted to the study the water flow structure formed in a glass tube with an outer diameter of 10 mm by multicolor particle image velocimetry (MPIV). The multicolor particle image velocimetry method is one of the modern modifications of the particle image velocimetry. The main difference between MPIV and classical particle image velocimetry is the number of probing laser planes. Three laser planes of red, green and blue radiation are supposed to be used for MPIV measurements. Such modernization makes it possible to visualize the flow structure and obtain velocity vector fields simultaneously in three planes. The paper formulates an algorithm for carrying out MPIV measurements and processing the recorded data. An experimental setup was developed and assembled, a series of MPIV measurements was carried out, the structure of the water flow was visualized, velocity vector fields in three laser planes were obtained, velocity distributions in the horizontal section of the tube were constructed.