Heat stress or elevation in temperature is one of the important abiotic stresses which is the limiting factor for the agriculture and can be the main reason to put the food security at high risk. According to IPPC, due to increase in the greenhouse gases the global warming results in the elevation of temperature and ultimately causes various morphological, biochemical and physiological changes in the crop or plants. The injury or damage caused by the heat stress can be on the photosynthesis system, electron transport system, anthesis in floret (result in the pollen dehiscence earlier which causes poor pollen dusting, shortening of the stamen), imbalance in the water and nutrient, disturbance in the assimilate distribution form source to sink or assimilate partitioning get disrupted, grain filling get disturbed and finally hamper their growth and development of the plant or crops and results in the yield loss as there is loss of biomass and grain weight. Different crop responds in different way to the heat stress, even at different species level some plants respond as tolerant to the heat stress because they have heat resistance gene or adapted to the stress situation by different morphological, biochemical and molecular modification. With the study of the above tolerance, resistance gene and the molecular response to the heat stress in the different crop, we can conclude with the best mitigation strategy for the management of the heat stress.