The invention relates to the field of agricultural 
outlier detection, in particular to an 
outlier detection method based on agricultural 
big data. The method comprises the following steps: a data collection step of collecting agricultural production data, agricultural soil data and agrometeorological resource data, and integrating the data into a training 
data set; The step of constructing iTree tree is to select m sample points from the training dataset and continuously randomly select splitting attributes and splitting points until the termination condition is reached; the step of constructing iTree tree is to select m sample points from the training dataset. Constructing an isolated forest 
algorithm model, initializing the number t of iTree trees in the isolated forest and the set m ofsubsamples taken when constructing the iTree trees, entering the step of constructing the iTree trees in a loop, and constructing mutually independent iTree trees, wherein the set of all iTree trees constitutes the isolated forest 
algorithm model; An 
outlier judging step of calculating an outlier 
score s (x), and judging whether the 
test data x is an outlier by the outlier 
score s (x). The invention applies the isolated forest 
algorithm model to the outlier detection of the agricultural 
big data, and can effectively improve the detection effect of the outlier of the agricultural 
big data.