Abstract: The paper reviewed meanings, examples, evolution and genetic traits of plant tolerance against insect pests and its potential mechanisms, as well as abiotic and biotic factors affecting expression of plant tolerance. Potential mechanisms of tolerance including photosynthetic activity, reallocation of available assimilates, change in inner hormone, compensatory growth and activation of dormant meristems, utilization of stored reserves, and changes in plant phenology and plant architecture after the damage. It has been found that there is no direct relationship between photosynthetic activity change of plants after insect pest damage and its tolerance:  for some plants the photosynthetic activity is increased, some unaffected, or even reduced. After damage, assimilates of tolerant plants are utilized to the greatest extent, dormant meristems is activated and vercompens ation is induced. Insect damage induces a significantly increased supply of leaf cytokinins or root_derived cytokinins in damage place of tolerant plants. Less change in plant phenology may be one of the more widespread mechanisms of tolerance. Plant size, leaf morphology, root_shoot rations, stem number and so on are related to its tolerance. Main factors affecting tolerance expression are  temperature, global CO₂ levels, soil nutrient available levels, agrochemicals, plant ages, distribution type and feeding strategies of insects, plant mutualisms, pollinators, endophytic fungi, mycorrhizal fungi and facilitating plants.  Under different temperatures the same plants may have different tolerance to the same pest species. The main cause is that change of temperature results in allocation and reallocation of available assimilates and effects of spiracle closing on gas exchange and photosynthetic ability. Plants grown in high CO₂ concentration has stronger tolerance. Soil nutrient level has stronger effects on plant tolerance expression than temperature. High concentration of phosphorus and potassium increases tolerance level. The distribution type of insects within a field can affect plant compensation for damage, and feeding pattern of insects, pollinator movement, infection of endophytic fungi and mycorrhizal fungi can also influence plant tolerance. The importance and application prospects of plant tolerance in integrated pest management were also discussed.

Key words: Plant, plant-insect interaction, insect damage, tolerance, compensation, mechanisms