Optimization of land use usually focuses on quality structure as it considers the maximization of economic, social, and ecological benefits as the goal. However, space structure optimization of land use under tourism ecological security constraints is hardly done. On account of this situation, only if the optimization of quality structure as well as space structure is taken into practice under the constraints can comprehensive land use efficiency and ecological environment improve in tourist cities. A typical tourist city, Zhangjiajie, was used as a case study to construct an tourism ecological safety evaluation index system, and the optimal land use structure under the tourism ecological security constraints based on the Lingo model were determined using the Grey linear programming method; in addition, measures were taken to configure the optimized parameter structure in space according to distribution rules, and finally, to optimize land use space with the help of the CLUE-S model. The results showed that 1) the comprehensive index of tourism ecological security in the year 2015 was 0.7394, indicating a relatively safe state. Specifically, that of the environmental pressure on tourism resources was 0.3231, that of the tourism environment condition was 0.2789, and that of the security degree of the humanistic social response of tourism scores was 0.1374; thus, the tourism environment condition and the security degree of the humanistic social response of tourism are lower than the environmental pressure on tourism resource. 2) Under the optimization of quantity structure, the areas of woodland, water and construction land apparently increased, while the areas of cultivated land, grassland, and unused land decreased. Predictably, the comprehensive index of tourism ecological security in the year of 2025 was 0.8196, which was 0.0802 higher than that in the year 2015, but which also indicated a safe state. Thus, the optimized quantity structure of land use plays a significant role in the ecological security of tourism. 3) Under the optimization of spatial structure, many positive changes have taken place in land use, and they all present more reasonable spatial distribution of land use. Woodland is distributed mainly in mountains and hills in Sangzhi County, Cili County, Wulingyuan District and the southern part of Yongding District; construction land is mainly concentrated in Cili County, Sangzhi County and the urban area of Yongding District; grassland is mainly located in the mountainous areas of Sangzhi County and Cili County as well as Wulingyuan District; cultivated land is distributed mainly in plains and hills of Cili County and Yongding District; utilized land is distributed sporadically in Cili County, Sangzhi County and Yongding District. In conclusion, the results of the study will provide Zhangjiajie City with technical reference points that will facilitate sustainable use of land resources and construction of tourism ecological security.