Chloramphenicol (CAP) has been being used to cure bacterial infections in human health, vegetarian or even in livestock farming. However, the overuse of CAP can bring many fatal side effects including blood dycrasias, leukopenia, gray skin. Due to the toxicity to humans, CAP is banned from agricultural products. However, it is still found in many agricultural products. As a result, there have been many sensing methods which were developed to determine the concentration of CAP in food. Among the developed methods, electrochemical sensing is one of the most popular way due to its simplicity, high selectivity, stability and sensitivity. To improve the performance of electrochemical sensors, people usually modify working electrode of sensors some types of material. In this study, I fabricated nanoparticle ZnCo₂O₄ and investigated the influence of temperature on electrochemical detecting performance of ZnCo₂O₄ towards CAP. The study indicated that the optimal temperature of heat treatment for ZnCo₂O₄ was 600 ℃. The material annealed at 600 ℃ showed a good sensitivity with limit of detection over CAP was 0.15 μM in PBS solution. The sensor modified with ZnCo₂O₄ also showed great selectivity with CAP and excellent stability during 30 days. The utilitarian application of the sensor was also investigated by surveying in the milk solution containing CAP. The sensor did not display any significant change in relative to the result in PBS solution demonstrating the application of the material in detecting CAP in real sample.