A long wave infrared (8-12.5 μm) focal plane array can not operate better than medium and short wave ones in many respects. Its non-uniformity and blind-pixel problems are quite serious. A MARS VLW RM4 320×256 HgCdTe long wave infrared focal plane array detector with a wavelength response range from 7.7 μm to 12 $\upmu$m is imported from Sofradir Company in France. On the basis of a high frame frequency and low-noise information acquisition system of which the dynamic range is calibrated, a thermal infrared imaging system is developed. Its dynamic range is from 250 K to 330 K and Noise Equivalent Temperature Difference (NETD) is less than 50 mK. According to the response characteristics of the pixels in the array detector, the non-uniformity and blind-pixel correction method suitable for thermal infrared imaging systems are studied. A non-uniformity and blind-pixel detection method based on radiation calibration is put forward. The experimental result shows that the method is better than the two-point method. It is easy to be implemented in engineering. The result based on radiation calibration is useful for more precise temperature inversion.