The existing size measurement methods have low accuracy and time-cons uming and laborious measurement.In order to improve the accuracy of dimension measurement,make the measurement system porta ble and easy to operate,a precise dimension measurement system based on linear CCD is realized in this paper.A new method o f subdivision of pixels is proposed in this paper.By staggering two linear CCDs with 8um pixel spacing equally and placing them obli quely at 60degrees,it can break through the limitation of pixel spacing on measurement accuracy and reduce the maximum measu rement error to 2μm.On this basis,the floating threshold method is used for data processing to achieve high-precision size mea surement.The drive of linear CCD is realized by hardware description in FPGA,the output signal of CCD is amplified differently, the electronic noise in the process of exposure integration and transfer is eliminated by hardware filtering method,the paralle l output of digital quantity is realized by 10-bit analog-to-digital converter,and the digital result is stored in FIFO in FPGA. The system makes full use of the programmable resources of the FPGA,effectively reduces the complexity of hardware design,does not nee d the upper computer or ARM,saves costs,and makes the system miniaturized and portable.Experiments show that the system can effec tively overcome the influence of light source and electronic noise.It can measure medium-sized objects of 1mm－29mm,and the err or is less than 2μm.