Calcium as a ubiquitous messenger participates in the pathophysiology progresses of various cells. Synchronized calcium signaling transduction is related to normal cardiac myocyte excitation-contraction coupling and beating rhythm. Calcium homeostasis abnormality in atrial myocyte is an important influencing mechanism of atrial fibrillation (AF), and it is mostly resulted from calcium leak caused by destabilization of sarcoplasmic reticulum calcium release channel ryanodine receptor 2 (RyR2). Calcium leaks, including calcium sparks and calcium waves, can trigger extra depolarization and even action potential, and cause AF on the basis of atrial pathology altering matrices. In this review, we summarized the manifestations and influencing factors of calcium leak, and its potential role in the development and progress of AF.