The invention provides a method for generating dozens of megampere pulse currents and a z-pinch direct drive source. The drive source comprises a primary pulse power source (thousands of fast discharge branch circuits are connected in parallel), a high-voltage transmission cable, a water medium electromagnetic induction chamber, a secondary MITL (Magnetically Insulated Transmission Line) and a z-pinch load, wherein the secondary MITL is formed by connecting multi-stage induction chambers in series; the z-pinch load is located on an axis; thousands of primary discharge branch circuits are located at the peripheries of the induction chambers and are divided into dozens of groups; the primary discharge branch circuits discharge rapidly to directly obtain an electric pulse with a leading edge of 100-200 ns, a voltage of 100-200 kV and a current of 30-50 kA. Currents of the thousands of branch circuits are transmitted and gathered on cable interfaces, which are uniformly distributed at the peripheries of the induction chambers, of dozens of I-shaped tri-plate transmission lines through the cable; the currents are gathered to the induction chambers for primary excitation through the tri-plate transmission lines; and the current gathering is realized through electromagnetic induction. Multi-stage induction chambers are connected in series to form an IVA (Induction Voltage Adder); the MITL is employed for a secondary stage of the IVA to realize voltage superimposition and power transmission; an ultra-high power electric pulse with a voltage of dozens of MV, a current of dozens of MA and a leading edge of 100-200 ns is generated on the Z-pinch load of the axis, and the requirement of a drive current of a Z-pinch ICF (Inertial Confinement Fusion) is met.