This paper presents the development of a gas-jet micropump with different cross-junctions and integrated hotwire. The device is actuated by a piezoelectric lead zirconate titanate (PZT) diaphragm at its resonant frequency. The design focuses on a cross-junction formed by the intersection of the channels and neck of the pump chamber, which allows differences in fluidic resistance and fluidic momentum during each PZT diaphragm vibration cycle and thus enables rectification of the gas without valves. Three different designs were investigated by utilizing the ANSYS-FLUENT software. Simulations and experimental data revealed that the step nozzle structure with anti-choking space has much more advantages than the others. The device has been fabricated by the standard MEMS process, and the tiny hotwire has been realized together with the fluidic network. Experiments have been carried out. At a driven frequency of 7.9 kHz, a flow rate of 5.2 ml min⁻¹ was obtained with an applied sinusoidal voltage of 50 V_p-p. The output voltage on the hotwire was measured to be 130 mV at a constant current of I = 0.1 mA.