A high spatial resolution ghost imaging technology based on cosine encoded multiplexing is demonstrated. Firstly, many low spatial resolution cosine encoded patterns are constructed and multiplexed to produce high spatial resolution modulation patterns, and then the high spatial resolution modulation patterns is used to illuminate the object. A single-pixel detector collects the backscattered light generated by the interaction between the modulated light and the object, and the mixed image of the object can be recovered by applying an iterative algorithm. Given the certain deterministic spectrum structure of the employed cosine encoded matrices, the low spatial resolution images of the object can be decoded and reconstructed efficiently using the digital image processing method, and finally spliced into high spatial resolution object images. The implementation method of the proposed cosine encoded multiplexing high spatial resolution ghost imaging is analyzed theoretically, and the effectiveness of the proposed method is verified by numerical simulation. It is shown that the proposed method greatly reduces the modulation patterns required for traditional high spatial resolution ghost imaging, reduces the online sampling time and the offline reconstruction time, and improves the imaging efficiency of high spatial resolution ghost imaging.