For increasing the output powers without improving drive currents to high power Vertical Cavity Surface Emitting Lasers(VCSELs), a VCSEL in series structure was presented. First, the VCSEL chips were soldered on a AlN ceramic heat sink, then the chips were connected by a wire bonding in series. The output powers of four-chip devices in series, two-chip devices in series and a single device were measured under microsecond and nanosecond pulses, which are 775, 416, 217 mW and 18.9, 9.8, 5 W, respectively. Test results show that the output powers of the first two kinds of devices in series are about 4 times and twice that of the single device. Moreover,the Full Width at Half Maximum(FWHM) of multiple-chip devices in series is slightly wider than that of the single device, which can be improved by choosing good uniformity cascade chips. In conclusion, the VCSEL in series structure can increase the output power without improving the drive current.