I want to choose stepper motor screw with slider for use it to shift cube with side 5 cm and wight 250 g .
I found this motor .. how can I calculate speed and torque of slider
This has a slightly longer answer than you may prefer, but the extra knowledge is necessary to get your result.
The useful values there are the 4-6V, 500mA, and the 3mm pitch. The motor will give you up to 3 watts of power. Power = torque x speed (kinda, I oversimplify slightly but its accurate). Now here's where the stepper can be handy: you can run it 'slowly'. Take a look at the charts on http://www.orientalmotor.com/stepper-motors/technology/speed-torque-curves-for-stepper-motors.html You don't need to study the charts in too much detail; just notice that slope, showing that they have the most force at around 200-400 RPM, almost regardless of the particular motor. Also, stepper motors often are combined with gears - that exact website sells them, and you can reduce the gearing beyond 30:1 if you want it to move really slowly. That website just so happens to have a calculator for this exact application! http://www.orientalmotor.com/motor-sizing/ballLeadScrew-sizing.html
Just be aware that you'll need at least an Arduino board and a special driver for a stepper motor. They operate differently from other motor types, hence why they have 4 wires.
I wish I could give you easier answers, but unfortunately I've not found simple answers for electric motors either. The easiest way to start is to get a simple DC motor or geared DC motor (more extreme gearing means more power, but slower) and you could attach it to a setup like that to spin the screw. You may still want/need a controller circuit for it.
I would use input electrical power as a guideline for the output mechanical power. Power is voltage times current, (in volts and amps for a power in watts), and power is also force times speed (in newtons and meters per second for a power in watts). I would assume the motor is 80% efficient and the screw is 70% efficient for some reasonable ballpark estimates.
You can convert revolutions to linear motion via the pitch - every revolution is 0.003 meters. The rated motor speed isn't listed, but you can use it to get the rated linear speed. Efficiency losses will "eat" your output force.