This paper reports in detail a regular interstratified mineral which occurs in a interformation structural zone of a certain uranium deposit. The mineral was determined by analytical data of electrical microscope, differential thermal, infrared absorbed spectral and X-ray diffraction analyses. The mineral has(001)， (002) reflection at 30.26A, 14.73A which expanded to 32.01A, 15.45A by treat- went with ethylene glycol, and contracted to 23.50A, 12.18A after heating to 550C. Finally, as compared with known data, It was confirmed that the clay is a 1:1 regular interstratified mineral of trioctahedral chlorite-montmorillonite. The mineral can absorb uranium up to 0.26%，i, e,. it is closely related with urmlium. This is the first discovery of 1:1 regular interstratified mineral chlo- rite-montmprillonite which has a high uranium content in China.