Abstract: Cycad revolute and cyanobacteria,which was isolated from the coralloid roots of the cycad and the surrounding soil,were reconstituted in the laboratory.The identities of the cyanobacteria were confirmed by amplified STRR primer and sequenced 16S rRNA.Comparing the STRR fingerprinting and 16S rRNA sequence,it was determined that the isolated cyanobacteria RZHA4 were able to infect the host plant.The strain RZHA4 showed high comparability with Nostocaceae cyanobacterium IL13-1 by blasting the NCBI.