This paper reports a single cell assay in compact disc (CD)-like lab chip with trapped single cells by centrifugal force. The main propose of this study was realization of cell assay on chip with the advantage of excluding the paracrine effect of adjacent cells. The channel in CD-like lab chip has many pitfalls at the outer side, in which cells were trapped respectively. The trap was able to fix each cell and the chemicals were treated by centrifugal pumping. Parameters that affects the trapping of a cell were the size of cells, the structure of micro-pattern, the magnitude of centrifugal force and the duration time. The trap ratio of cells was around 80% at optimal condition. Cytotoxicity and apoptosis test was done in CD and it was compared with conventional method to see the effect of single cell assay. Cytotoxicity was tested by the treatment of parformaldehyde and the apoptosis test was done by illumination UV light. The results of both assays indicated the overall trend of single assay in chip and conventional assay was same. However, apoptosis assay showed that the survival rate of single cell assay in chip was higher than that of conventional assay. Although it is still unclear that the result was caused by the effect of crowded cells, this single cell assay platform could be one of valuable tools in single cell assay.