In the context of developing countries, medical instruments are imported from foreign countries. To overcome this challenge, the design of an oxygen analyzer using ultrasonic flow sensor technology and a microcontroller while promoting local innovation and reducing dependency on imported equipment is presented here. Moreover, it aims to enhance patient care by ensuring accurate oxygen concentration and flow rate measurements on ventilators and oxygen concentrators. The proposed system works well compared with the existing standard system. The measure data using the proposed system has been validated by comparing it with the data obtained using the standard oxygen analyzer equipment like VT-900 Gas Analyzer Fluke Biomedical and Ultra Max oxygen analyzer. Measurements were conducted on hospital ventilators with oxygen concentration which is also called fraction of inspired oxygen(FiO2) settings from 21% to 100% in 5% increments and flow rate settings from 1L/m to 10L/m. Results show an error value of 2.1% for oxygen concentration and 0.6 L/m for flow rate measurements. Based on the analysis, it can be concluded that the proposed system works well. Additionally, it offers portability, affordability, and user-friendliness, overcoming the limitations of existing options. This project seeks to contribute to the healthcare infrastructure in developing countries like Nepal, India, Bangladesh etc by providing a domestically produced solution for oxygen analysis.