The invention discloses a risk assessment and emergency decision-making method for forest fire disasters of a power transmission line. The risk assessment and emergency decision-making method comprises the steps of: calculating probability of field forest fire causing trip of the power transmission line through combining a power transmission line forest fire tripping mechanism, calculating load loss after trip of the power transmission line, and assessing value-at-risk of trip according to the trip probability and load loss; and then calculating field forest fire handling priority of the power transmission line according to a voltage class of the power transmission line, forest fire trip comprehensive load loss amount and forest fire trip value-at-risk, and giving an optimal decision-making scheme of configuring available resources scientifically. By adopting the method, the effect of handling the forest fire quickly and accurately according to the optimal scheme can be achieved, the method is novel in idea and is clear in process, and can provide efficient and economical technical means for handling the forest fire of the power transmission line in the field.