Abstract: A chopper was used to change a diode bar with a center wavelength of 780 nm from continuous laser to pulsed laser, and a Littrow external cavity was build with a 2400 l/mm plane grating to narrow the linewidth of the diode laser to less than 0.2 nm. Then the diode laser was shaped by a lens group. After the linewidth narrowing and beam shaping, the laser was focused to a Rb vapor cell with a length of 8 mm. In that diode pumped alkali vapor laser system, a linearly polarized fundamental mode Rb laser with a peak power of 17.5 mW was obtained. In the latest experiment, we obtained a 2.8 W Rb laser in the improved diode pumped rubidium vapor laser system.