The output power of highＧpower tunnel junction laser is limited by the catastrophic optical damage(COD)．To solve this problem,the COD threshold value of the high-power tunnel cascade was improved by optimizing the material structure of the devices．Inthis paper,a single tunnel junction laser chip with the strip width of 200μm and the cavity length of 900μm was fabricated．Experimental results show that under the conditions of pulse frequency of 5 kHz and pulse width of 200 ns,the peak power of the fabricated laser exceeds70 W at room temperaturewithnoobviousCOD．Attheoperatingcurrentof２０A,thedesignedlasershows the peak wavelength of 907nm,spectral width of 7nm and slope efficiency of 1.88,which is about two times that of the single active layer lasers at the same operating current．