Abstract: A microfluidic chip (100) for capturing cells (200) and preparing method thereof. The chip (100) comprises an upper rigid material (10) and a lower rigid material (20), a channel (30) provided between the upper rigid material (10) and the lower rigid material (20). The channel has an inlet (32) and an outlet (34). At least one of the upper rigid material (10) and the lower rigid material (20) is made of transparent material. The channel (30) has a height decreasing gradually from the inlet (32) to the outlet (34), thus a wedge shape is formed, or a portion of the channel has the wedge shape. The lowest portion of the channel (30) has a dimension approximate to or less than that of at least one of target cells. The chip (100) could quickly, effectively separate and enrich cells with various sizes and specific molecular expressions.