In some countries, including China, primary health care is rarely utilized because of medical personnel shortages at primary medical and health care institutions (PMHCIs). Several studies suggest that the most effective solution is to guide qualified doctors and medical graduates to work in PMHCIs, but the studies and measures have been formulated only from the perspective of the government and PMHCIs; few have considered the subjective willingness of medical personnel. Therefore, it is necessary to explore the measures to develop human resources of PMHCIs from the guiding object. This research was divided into two parts based on implicit theory and a lexical approach. The first part collected the factors affecting their choosing PMHCIs for employment, and the second part used exploratory factor analysis (EFA), confirmatory factor analysis (CFA), and structural equation modeling (SEM) to explore the dimensions and paths of the influencing factors. At last, seven factors were obtained from the EFA, and the SEM hypothesis fit the data well. Internal Organization Development, Patient Factor, Remuneration and Development, and Family Support had a significantly positive effect on the Sense of Gain of medical personnel seeking employment at PMHCIs, whereas both Job Responsibilities and Condition of the City Where the PMHCI Is Located had no significant effect. In addition, the indirect effects of Internal Organization Development and Condition of the City Where the PMHCI Is Located on the Sense of Gain were significant. The Patient Factor, Family Support, and Remuneration and Development significantly mediated the relationship between the internal and external environment of the institution and the Sense of Gain, whereas the mediating effect of Job Responsibilities was not significant. The improvement of family support, remuneration and development, and patient factors increase the willingness of medical personnel to seek employment at PMHCIs. In addition, the internal and external environments of a PMHCI play a vital role in guiding medical personnel to PMHCIs for employment. This research provides theoretical support for improving the development of human resources, guiding medical personnel to work in PMHCIs, and promoting the use of primary care services.