Environmental　temperature　exerts　significant　influences　on　neuronal　firing　and　information　encodings.　Concepts　on　the　mechanisms　of　the　respective　effects　are　still　elusive　and　controversial.　In　our　study,　we　examined　the　effect　of　temperature　on　firing　patterns　in　a　model　cortical　pyramidal　neuron.　It　was　found　that　a　variety　of　firing　patterns　is　obtained　under　different　temperatures.　In　addition,　the　transition　modes　between　these　firing　patterns　display　a　clear　periodic　bifurcation　phenomenon　when　the　temperature　varies　within　a　certain　range.　Several　typical　bifurcation　modes　were　found,　in　particular　period-doubling　bifurcation　and　period-adding　bifurcation.