Recently,　Deep　learning　has　made　a　great　deal　of　success　in　processing　images,　audios,　and　natural　languages　and　so　on.　The　activation　function　is　one　of　the　key　factors　in　Deep　learning.　In　this　paper,　according　to　characteristics　of　biological　neurons,　an　improved　Leaky　Single-Peaked　Triangle　Linear　Unit　(LSPTLU)　activation　function　is　presented　for　the　right-hand　response　unbounded　of　Rectified　Linear　Unit　(ReLU)　and　Leaky　ReLU　(LReLU).　LSPTLU　is　more　in　line　with　the　biological　neuron　essence　and　achieves　the　excellent　performance　of　equivalent　or　beyond　ReLU　and　LReLU　on　different　datsets,　e.g.,　MNIST,　Fashion-MNIST,　SVHN,　IMAGENET,　CALTECH101　and　CIFAR10　datasets.