The invention relates to a 
cloud workflow task 
execution time prediction method based on limit gradient improvement, and belongs to the technical field of 
cloud computing. According to the method, influence factors of task 
execution time are classified from three levels of 
workflow task composition, resources on which task operation depends and a physical execution environment of the resources, and comprehensive modeling of the influence factors of the task 
execution time is achieved. Secondly, aiming at the condition that the sample 
data set has a data missing value, the 
data set with the missing value is complemented by adopting a 
machine learning method; and finally, by means of the multi-type 
data processing capability of the extreme gradient lifting 
algorithm, the 
parameter design isrelatively simple, the calculated amount is small, the advantages of a serial learner and a parallel learner are combined, and a 
cloud workflow task execution time prediction model is trained by adopting the extreme gradient lifting 
algorithm. Compared with an existing prediction model, limitation on the sample 
data type is reduced, prediction errors are reduced, and the generalization ability ofthe model is further improved.