Provided are a fungus-sourced high-temperature neutral Family-45 cellulase as well as a coding gene and an application thereof. The cellulase has the optimal pH value of 5.5 and the optimal temperature of 60 DEG C, has certain enzyme activity in alkaline conditions and has good alkali resistance, maintains about 70% enzyme activity in the optimal condition after being processed at 90 DEG C for 1 hour, maintains about 50% enzyme activity in the optimal condition after being processed in boiling water for 1 hour, and can be well applied in textiles, paper-making and other fields.