Controlled graphene or its derivatives' assembly is of growing interest in many areas. However, achieving control over their assembly into precise and predictable architectures has been challenging and is still a bottleneck to their utilization. Herein, we report for the first time the use of DNA hybridization for the controllable assembly of a graphene nanosheet. Moreover, with the help of dynamic light scattering technique, we extended the above studies by exploiting the DNA-graphene dispersed sheets as highly ultrasensitive detection of oligonuleotides for the fabrication of a novel biosensing strategy, which shows high sensitivity and excellent selectivity. This work will show a new general route to graphene-based lamellar composite materials and would bring about advances in the research of graphene-based biofunctional materials for specific applications in biodiagnostics, nanoelectronics, and bionanotechnology.