投資者同股東既分別???

They all are investors. If the company is a limited company issuing shares to investors paying in money to the company as capital, we then call them shareholders. If the company is a firm or an unlimited company, the investors injecting funds to the company means they are holding the proportionate share of interest e.g. 10%, 30% etc of the total capital of the company as mutually agreed by all investors. A partnership of 50% : 50% means there are 2 investors, partners, with 50% of interest of the partnership business. This is a strict definition of investors. Investors = Shareholders = Owners of the business.
If a person is simply injected a sum of money to a business without the ownership but for a return say, 5% of the sum 'invested', they are strictly not an investor but a financier.