Tungsten carbide-cobalt (WC–Co), as a typical cemented carbide, is widely used in the manufacturing field. However, creating high-quality microstructure arrays on its surfaces remains challenging due to its extraordinary hardness. To solve this problem, this study proposes an in-situ laser-assisted ultraprecision cutting (LAUC) process to machine different microstructure arrays on the WC-Co surfaces. Experimental results show two kinds of microstructure arrays, namely bi-sinusoidal microstructure array and micro-lens array, are successfully created on the WC-Co surfaces. The average error of feature sizes is less than 2%, showing the high cutting accuracy of the in-situ LAUC process. The average surface roughness of microstructure arrays is below 6 nm, showing the high cutting quality of the in-situ LAUC process. Furthermore, a comparison experiment with the traditional ultraprecision diamond turning process shows the proposed in-situ LAUC process improves the machinability of the WC-Co and decreases the tool wear, further demonstrating its superiority. Therefore, this work provides a new and effective method of creating microstructure arrays on WC-Co surfaces, which greatly enhances the machining quality and extends tool life.