Abstract: Evaporators with different structural types have different heat transfer coefficients. In this paper, the authors chose six evaporator models with different structures, to analyze and compare the influences of fin shape, tube diameter and tube arrangement on heat transfer coefficient of an evaporator. The conclusion is that, under freezing circumstances, the structure with the highest heat transfer coefficient is the one with continuous unitary plate fins with wave, cross pipe arrangement and varying fin spacing. Then the authors made an experimental investigation on this type of evaporator, and obtained a heat transfer coefficient in line with theoretical calculation.