Abstract： This paper aimed to find out the law of friction factor relative to the parameter of rotor rotating in the annular channel between the rotor and the stator of the canned pump. The distributions of pressure drop at different rotor speeds were measured by a scale test rig. The experimental results indicated that with the rotational speed increasing, the pressure drop between the inlet and the outlet also increases, and the original empirical formula of friction factor in an annulus channel is no longer suitable and should be revised. The function relationship between the revision factor and ratio of tangential/axial Reynold numbers was obtained by using data analysis. Thus, the revised formula of friction factor affected by tangential flow was derived. In order to verify the accuracy and universality of this formula, the flow characteristics and pressure drop of the fluid in the scale test rig and in the canned pump were studied by using the  computational fluid dynamics (CFD) method. The results showed that the bias of the friction factor calculated by simulation and the revised formula is small enough to be considered in a reasonable range.