The flow field and pressure loss coefficient of rectangular inner channel at right-angled bend are studied by the finite volume method. Specifically, the influence of channel size, coolant flow rate and coolant volume fraction on the local flow field and pressure loss coefficient is analyzed. The result shows that the pressure loss coefficient decreases gradually with the increases of the channel width a and the channel height b, and decreases and then increases slightly with the channel interval e. The change of bend width c causes the change of local flow field in bend and the pressure loss coefficient. The greater the flow velocity is, the smaller the pressure loss coefficient is. The greater the volume fraction of the cooling fluid is, the larger the pressure loss coefficient is.