With the continuous development of light emitting diode (LED) technology, high-power LEDs with various wavelengths have been developed, therefore we can design a LED-based QE instrument using LED with various wavelengths as monochromatic light source instead of expensive monochrometers. Compared with the traditional QE instrument, there is no filter required in the LED-based QE instrument, so it is not necessary to rotate the filter wheel for a grating monochrometer to avoid the influence of high-order spectrum. Without mechanical movements, which reduces the failure rate and speeds up the measurement. Several LEDs are welded on a printed circuit board (PCB) as the discrete light source. However, it is impossible to converge light as the traditional QE instrument using ellipsoidal mirror, lens or concave mirror. Therefore, the discrete light from the LED board is collected and homogenized into a small spot by a light pipe formed with highly reflective reflectors, which can solve the difficulty in converging discrete light sources and the high utilization ratio of light is achieved. By measuring the peak intensity, full width at half maxima (FWHM) and stability of LED, and further comparing it with the traditional QE instrument using halogen lamp and xenon lamp as light source, it is found that the measurement accuracy of QE is positively correlated with the peak intensity of monochromatic light. The higher the peak intensity is, the higher the measurement accuracy is. Furthermore, it is also observed that the measurement accuracy has no obvious correlation with FWHM in the range of 2.5~9.5 nm. The QE of the same solar cell is measured by LED-based, halogen lamp-based and xenon lamp-based QE instrument, respectively. The integrated current is further calculated based on QE in the same wave range, and compared with that obtained from the advanced xenon lamp-based QE instrument, it is found that the relative error of the LED-based QE instrument is only 0.34%, which is equivalent to the accuracy of the halogen lamp-based QE instrument. Based on integrated current conditions, the measurement accuracy has no obvious correlation with the FWHM of LED varies from 8.3~55.7 nm. Moreover, the instability of LED is 0.4%, which is between xenon lamp and halogen lamp. Based on these three aspects, it can be concluded that LED can be used as the monochromatic light source for QE measurement.