Abstract: The purpose of the study aims to construct a complete theory that clarifies the causes and rich connotations of blood laminar flow spectrum in transcranial doppler ultrasound. According to the theory of hemodynamics and hemorheology, the innovation hypothesis is that the blood of the straight blood vessels in time interval Δt follows the Poiseuille Flow, and the key innovation concepts such as the thickness and division of the flow layers, the division of the spectrum are applied. The red blood cell density, the volume of the stratum and the distribution of the number of red blood cells contained in the stratum in time and space are scientifically demonstrated. Finally, three innovation conclusions are obtained. This study builds the theory of expectations.

Key words: doppler ultrasound, doppler blood flow spectrum images, effects of red blood cell concentration