The invention discloses a microfluidic cell culture chip guaranteeing uniform cell distribution and a cell sample introduction method. A main flow channel and auxiliary flow channels which are cross and vertical to the main flow channel are formed in a substrate, each auxiliary flow channel is a step-shaped flow channel which is granularly widened from the outer end to the middle, and the bottom surfaces of the auxiliary flow channels are higher than the bottom surface of the main flow channel; firstly, a culture solution is injected into a culture chamber, a cell suspension solution is injected into the culture chamber after the bottom of the culture chamber is filled with the culture solution, the culture solution is injected into the main flow channel after a certain quantity of the cell suspension solution is injected into the main flow channel, the culture solution pushes the injected cell suspension solution to the culture chamber, mixed gas enters buffer zones on two sides of the culture chamber through the auxiliary flow channels, the bottom of the culture chamber in the middle of the main flow channel is enabled to be filled with the cell suspension solution while the other space of the main flow channel is filled with the culture solution, therefore, cells are just distributed at the bottom of the culture chamber, no cells remain in the non-culture-chamber zone, and the cells are uniformly distributed at the bottom of the culture chamber.