NOVELTY - A polycrystalline silicon ingot is manufactured by forming seed crystal layer in polycrystalline silicon ingot growing furnace bottom laying seed crystal; and heating container, and melting silicon raw material and seed crystal layer, to form liquid layer. The solid-liquid interface moves to direction far away from bottom of the container, until obtaining polycrystalline silicon ingot. The bottom plate on lower part of the container has multiple crossed groove. The groove is located on same vertical surface with the gap between seed crystal and seed crystal container.    USE - Method for manufacturing polycrystalline silicon ingot for solar cell.    ADVANTAGE - The photoelectric conversion efficiency of the solar cell using the polycrystalline silicon ingot is improved.    DETAILED DESCRIPTION - Polycrystalline silicon ingot is manufactured by forming seed crystal layer in polycrystalline silicon ingot growing furnace bottom laying seed crystal; and heating container, and melting silicon raw material and seed crystal layer, to form liquid layer, where a part of seed layer in melting process, at bottom of the flute is inert gas, at least remaining in contact with bottom part of seed layer is solid. The solid-liquid interface moves to direction far away from bottom of the container, until obtaining polycrystalline silicon ingot. The bottom plate on lower part of the container has multiple crossed groove. The groove is located on same vertical surface with the gap between seed crystal and seed crystal container. The solid silicon source is loaded on seed layer An INDEPENDENT CLAIM is included for a polycrystalline growth furnace which comprises furnace body and supporting device. The supporting device comprises bottom plate, on bottom of container. The container is laid seed crystal layer and silicon raw material. On the bottom plate is provided with crossed groove. The groove and container laid gap between seed crystal and seed crystal are located on same vertical plane.