The invention discloses a lithium battery and a manufacturing method thereof, which belong to the field of batteries. The lithium battery comprises a positive pole, a negative pole and a diaphragm arranged between the positive pole and the negative pole. The manufacturing method comprises the following steps: making active matters into a mixed paste; preserving blank positions on the front and back sides of an edge in the lengthwise direction of a positive pole piece, coating the paste on other parts of the positive pole piece completely, preserving blank positions on the front and back sides of an edge in the lengthwise direction of a negative pole piece, and coating the paste on other parts of the negative pole piece completely; covering the pasted positions of the negative pole piece with the diaphragm, placing the positive pole piece, and staggering the blank positions of the positive pole piece and the blank positions of the negative pole piece at two ends respectively to arrange the positive pole with blanks at one end and the negative pole with blanks at the other end; welding the blanks of the positive pole with a positive pole tab and the blanks of the negative pole with a negative pole tab; and placing a battery cell welded with the pole tabs in a packaging shell, packaging the shell, drying the shell under vacuum, filling liquid, sealing the shell, and obtaining the battery after formation, capacity grading and examination. The lithium battery and the method have the advantages of reducing the distance from the pole pieces to pole terminals, internal resistance and heat generated during charge and improving safety, reducing pressure drop caused by internal resistance and discharge platform.