The invention discloses a tea tree NRT1 gene, a sequence of which is shown as SEQ ID No.1. The invention also discloses a tea tree NRT1 protein, a sequence of which is shown as SEQ ID No.2. The invention also discloses a gene expression method of the tea tree NRT1. A total length of the tea tree NRT1 gene sequence is 1880bp, 594 amino acids are encoded, the protein molecular weight is 65.92kD, and a theoretic isoelectric point is 9.07043. 12 transmembrane helical regions are contained, wherein a large hydrophilic ring exists between a sixth transmembrane helical region and a seventh transmembrane helical region. The protein is a hydrophilic protein, and the tea tree NRT1 is a constitutive gene. The mechanism for absorbing and assimilating NO3<-> in different tissue parts of a tea tree is shown to be possibly different, and the NRT1 is not only used as a nitrate transfer protein, but also is a signal acceptor sensing the nitrate.