The light-transport characteristics of the pericardium meridian and its surrounding non-meridian tissue are studied in vivo. An experimental scheme is established for noninvasively measuring the space distribution of diffuse light in an area including the pericardium meridian with the method of combination of dots and matrix. The distribution of diffuse light in the area are studied integrally. Two obvious linear dips are observed on the 3D image of the distribution of diffuse light, and their location coincides with the tendons on the two sides of the pericardium meridian. The study suggests that with this method the space distribution of diffuse light on the surface of body can be measured effectively. The experimental data is processed with the method of cubic spline interpolation. The study suggests that there is a significant difference between the propagations along the meridian direction and the non-meridian direction (p<0.05). In the five specific directions the light attenuation along the pericardium meridian is significantly less than that along the other non-meridian directions. The larger the angle between the meridian direction and the non-meridian direction, the faster the diffuse light attenuates along this non-meridian direction.