The authors describe in this paper the fundamentals of estimating relative paleomagnetic field intensity by the currently used nonthermomagetic met-hod, which utilizes DRM/ARM and/or DRM; SIRM as indicators in pa,leomag-netism of unconsolidated sediments. The feasibility and the advantage of ap-plying the method to speleothems (secondary deposits of limestone cave) are nga.Iso demonstrated. We applied the me thud to a stalagmite sample from Cruangxi, China and estimated the variation in relative intensity of paIeomagnetic field over the past 6000 years. "Che variation has three major features:1 .Several short-period oscillations of 1000 years are superimposed on a longer-periori oscillation.2. There are fiva maximum peaks and five minimum peaks in the variation.3. The present }eo:na}netic field intensity approaches the minimum value.