The invention discloses a wireless sensor abnormal data detection method based on unsupervised learning. The method comprises the following steps of 1, acquiring m pieces of data continuously acquiredby a wireless sensor node to form a training sample set; 2, establishing a quarter hypersphere support vector machine model of which the sphere center is located at the origin of high-dimensional space coordinates, wherein the minimum support radius is R; 3, optimizing the parameters of the 1/4 hypersphere support vector machine model by applying a particle swarm algorithm and a training sample set to obtain an optimized model; 4, obtaining m + 1 pieces of data Tq continuously collected by the wireless sensor nodes, calculating the distance d (Tm + 1) of Tm + 1 in the mapping space of the optimization model to the sphere center, and if d (Tm + 1) is smaller than or equal to R, determining that Tm + 1 is normal data; if d (Tm + 1) is greater than R, using a set {T1, T2,... Tm} as a training sample set to retrain the model, and calculating the minimum support radius Rnew, and calculating the distance d (Tm + 1) new from the Tm + 1 in the updated mapping space of the model to the spherecenter, and if d (Tm + 1) new < = Rnew, determining that the data Tm + 1 is normal data, otherwise, determining that the Tm + 1 is abnormal data. According to the method, the unsupervised learning isadopted, and the samples do not need to be labeled, so that the detection accuracy is higher.