With the increase of population and the demand of fishery resources, the trend of human fishing from high to low trophic level is still continuing, which could threat the marine biodiversity and benefits. It has been widely concerned that fishery-induced evolution (FIE) caused by overfishing has led to the general miniaturization of fishes. In this paper, we reviewed the role of big old fish in the process of population reproduction. The big old fish has huge reproductive-energy output and rich parental experience, which is more conducive to the continuation of their population. We believe that big old fish has played a leading role in the breeding migration of the first sexual maturation broodstock. The big old fish also can maintain the stability of the population structure by inhibiting the reproduction of small fish. Besides, the big old fish occupies a higher trophic level and expansive niche breadth in the ecosystem, which leads to stronger adaptability to respond to environmental changes. The big old fish also plays a key role in the process of population gene exchange. Therefore, it is indicated that the protection of big old fish would be more conducive to the rapid recovery of fish population, which can provide useful information for biological resources conservation and fishery administration.