The invention discloses a dietary fiber compound nutrient with a slimming lipid-lowering effect and a preparation method of the compound nutrient. The compound nutrient comprises the following components in parts by weight: 10-15 parts of tea tree pollen, 10-20 parts of oat flour, 5-10 parts of psyllium husk powder, 3-5 parts of chia seed oil, 3-5 parts of cranberry concentrated powder, 0.5-1 partof sodium citrate, 0.2-0.3 part of annatto, 0.5-0.8 part of tricalcium phosphate, 4-6 parts of konjac refined powder, 3-5 parts of a dandelion extract, 1-2 parts of a corn stigma extract, 5-6 parts of resistant dextrin, 1-2 parts of L-arabinose, and 3-5 parts of a mulberry leaf extract. According to the method, a special process is used to prepare the konjac refined powder and the chia seed oil,so that the content of starch and plant fibers in the konjac refined powder are reduced, browning is avoided, and the content of unsaturated fatty acids in the chia seed oil is improved; and the konjac refined powder and the chia seed oil are used with components rich in dietary fibers according to a reasonable ratio, so that the effects of effectively reducing sugar and fat and preventing obesityare achhieved.