The variation of pressure drop and flow pattern of nitrogen-water and nitrogen-CMC solutions in microchannels with different widths were experimentally studied, the effects of gas-liquid flow rate ratio and dimensionless number on pressure drop and bubble length were analyzed. The results show that the larger the flow rate and solution concentration, the smaller the microchannel width and the greater the pressure drop. In gas-liquid two-phase flow, the pressure drop decreases exponentially with the increase of gas-liquid flow rate ratio. After correcting the pressure drop model of separated phase flow, the error between the predicted value and the experimental result is -13.64%~17.41%. The bubble length prediction model is modified by accurate calculation of the bubble cross sectional area, and the error between the predicted value of the bubble length model and the experimental bubble length is less than 20% except for individual points. The prediction of pressure drop and bubble length of gas-nonNewtonian fluid two-phase flow in microchannel can provide design reference for microfluidic system.