Cell lysis performs as the first step in sample preparation for the diagnosis and treatment of intracellular genetic substance-based disease. In present, on-chip cell lysis is being developed using a variety of technologies such as mechanical, chemical, electrical and thermal for fast and simple point-of-care testing (POCT). Among cell lysis in microfluidic channels, the mechanical, chemical and electrical methods require complex channel design, reagent and high operation voltage than thermal method. Recently, nanoparticle (NP)-based photothermal lysis chip has been developed as one of the thermal methods in which nanoparticles are directly bound to cells and transfer heat to proceed cell lysis. However, NP-based photothermal lysis chip still have issues such as complex channel design and the requirement of additional equipment for cell capturing. Here we report nanoplasmonic photothermal cell lysis chip with high density Au nanoislands (HD-AuNIs). HD-AuNIs, fabricated by repeated solid-state dewetting to obtain the large diameter of Au nanoislands and narrow nanogap, exhibit enhanced light absoprtion in visible light range, which generates rapidly heat by photothermal effect. We check the cell viability to identify the cell lysis efficiency according to temperature and thermal exposure time. In addition, polymerase chain reaction are performed to check photothermal stability of DNA.