【Objective】The present experiment was conducted to clone the full-length sequence of mitogen-activated protein kinase （MAPK） in sugarcane to explore mechanism of stress resistance in sugarcane. 【Method】The total RNA was extracted from leaves of sugarcane variety ROC22 and the cDNA was synthesized by gene racer kit. Based on the cDNA sequences of the conserved regions of plant MAPK genes， a pair of primers was designed and synthesized for cloning the full-length sequence of a novel member of MAPK gene family by RACE reaction. The bioinformatics of the cloned MAPK gene was also analyzed. 【Result】The cloned mitogen-activated protein kinase gene from sugarcane showed 92.6% homology with ZmMAPK4， and it was named as SoMAPK4 （accession No. JQ062930）， which cDNA full-length was 1499 bp with a polyA tail of 23 bp， containing a 5'-untranslated region （UTR） of 218 bp and a 3'-untranslated region （UTR） of 213 bp. The cDNA contained an ORF of 1128 bp encoding a protein of 376 amino acids with a calculated molecular weight of about 43.5 kDa and a pI of 5.51. The SoMAPK4 protein contained 11 sub-domains of protein kinase with serin/threonine specificity and phosphorylation TEY motif of MAP kinase. 【Conclusion】A novel MAPK gene SoMAPK4 was cloned. The SoMAPK4 may be involved in many signal transduction activities for various stress reactions， and is the key factor for studying signal transduction during sugarcane biotic and abiotic stresses.