The act determining plans and procedures for the decentralization of power to local government organizations in B.E. 2542, requires the transfer of public health missions to local government organizations. Health promotion hospitals under the local government organization should provide health services for people based on the Primary Health System Act B.E.2562. The purpose of this mixed methods research was to 1) explore the standard of primary care, availability of primary care services, and the accreditation process of health promotion hospitals under the local government organization and 2) to analyze, synthesize and then provide recommendations for the standard delivery in primary health care and standard service delivery of health promotion hospitals under the local government organization. The participants were recruited using purposive sampling. The study was composed of 3 phases: phase 1 was documentary research to identify situation analysis of policy and law related to the decentralization and primary care act, health promotion hospital quality assessment guideline and standard health care service of health promotion hospitals; phase 2 was quantitative research to identify standard service delivery of health promotion hospitals and to determine availability and gap of primary care services after the transfer to a local government organization, and phase 3 was qualitative research using in-depth interview and focus group discussion with the stakeholder who is involved with standard health care service of health promotion hospitals. The research instruments were a semi-structured interview. The characteristic information from health promotion hospitals and local government organizations was collected by a questionnaire. All the questionnaires were developed and validated by five experts. The qualitative data were analyzed using content analysis and the quantitative data were analyzed using descriptive statistics. The results of this study revealed that: 1. The component of standard primary health care service includes: 1) determinants of health such as infrastructure, health workforce, health information, medicine, other medical supply, and digital health technology; 2) service delivery including prevention, promotion, treatment (acute and chronic) rehabilitation and palliative care in all age groups; and 3) health system objective such as outcomes and impact of service delivery 2. The improvement criteria of Tambon Health promoting hospital (star hospital) is the highest quality standard for primary health care service delivery accreditation. However, there were some limitations. For example, some assessment criteria were inconsistent with the local context, and the audit team from the district and provincial level assessed and helped to pass. There for no actual quality improvement in some areas. Another standard evaluation criteria for primary health service in Bangkok was developed by The Healthcare Accreditation Institute (Public Organization) that can be extended to use with primary care units throughout Thailand. 3. Primary care units should be accredited by an external organization composed of healthcare teams that include physicians, nurses, and pharmacists, who know quality assessment, apprehend the working system and are not a stakeholder. The audit includes both internal and external audits. The process of audit may use the same method as the previous year which is using the network partners and mentor teams to provide support and advice for quality improvement and participation of people in the community. 4. Health promotion hospitals that are going to transfer to local government organization state that the structural readiness to provide services were at the right level or higher. However, the number of health professionals and supportive personal readiness was at a low level. 5. Most of the health promotion hospital rate their availability to provide standard service delivery after transfer to the local government organization were the same and more quality in all health services except dental care and physiotherapy which is reduced.